1. Field of the Invention
The present invention relates to a nitride semiconductor device and a manufacturing method thereof, and more particularly, to a nitride semiconductor device in which a p-type nitride semiconductor layer is partially formed on a nitride semiconductor layer structure, and a manufacturing method thereof.
2. Description of the Related Art
There has been growing interest in reduction of power consumption due to green energy policy. To achieve this, improvement in power conversion efficiency is necessary. In the power conversion, efficiency of a power switching device has influence on the entire power conversion efficiency.
At present, most of power devices generally used are power MOSFETs or IGBTs using silicon. However, an increase in efficiency of the devices is limited due to material limitations of silicon. To overcome this, there have been patent applications which are to increase the conversion efficiency by manufacturing a transistor using a nitride semiconductor such as gallium nitride (GaN).
However, until now, since it is very difficult to manufacture a homogeneous GaN substrate and mostly, a GaN layer is formed on a silicon (Si), sapphire, or silicon carbide (SiC) substrate by heterogeneous growth, there is a difficulty in obtaining a high quality GaN substrate.
Accordingly, until now, since electrical characteristics can't follow theoretical values, studies for improving a withstand voltage in terms of design are in progress.